Self-cleaning punch



Feb- 27, 1940 D. E. sTRoMBERG E1- AL 2,191,836

SELF-CLEANING PUNCH Filed Sept. 23. 1938 INVENTOR. DA VID EI E'TEDMEEEE/'DSEFH E CAELEN 7a/144V 7 ATTORNEY.

Patented Feb. y27, 1940 PATENTv ortica SELF-CLEANING PUNCH David E.Stromberg and J oscph E. Carlsen, l Detroit, Mich.

Application September 23, 1938, Serial No. 231,297l jrs claims. (c1.164-110) This invention relates to an improved self-x.

cleaning punch or die.

An object is to provide a punch which is` simple, an inexpensive, whichis sturdy and of rugged rconstruction and which is entirelyself-contained and self-cleaning.

This improved punch is particularly designed for the cutting of fiber`board and other similar sheet material but is capable of use with sheet"material of widely varying characteristics and is intended for such usewherever itl may be feasible. Hereto-fore punches designed for this usehave required additional operations for removal ofthe slug or cut-outcut either from the sheet cf "material-upon which the punch operated vorfrom the punch itself if such Ycut out was retained by;

the punch after being withdrawn by the punch from the sheet.

vPunches have been provided with spring mech anism adapted to act uponthat portion cut from the sheet punched to eject such cut out portionfrom the punch itself after 4the punch has lifted the cut out portionfrom the sheet. Such spring mechanism, however, generally functioned toact .on said lcut out portionto eject the same concurrently with thelifting o-f the punch itself from the sheet and as a result suchcut outportion was v ejected from the punch itself back into the aper- Y turein the sheet. If the cutout portion could not pass -directly vthroughkthe aperture in the sheet or fall therefrom an additional operation wasnecessary for its removal.

Other types of punches have been provided wherein additional apparatusactuated by or responsive to mechanism on the press or punch operatingmechanism was brought. into play. to eject the cut out portion `whichVnormally remained with the cutting or knife part of the punch. `Suchpunches are not considered to be self-cleaning in that the cleaning ofthe punch is not accomplished by mechanism self-.contained within thepunch itselfbut by auxiliary mechanism.

.This improved punch while self-cleaning is also self-contained-in thatthe cut out portionor `slug severed by the cutting edge of the punch isejected from the punch by mechanism within the punch.

itself and is ejected in such a manner that. the

slug clears the aperture in the sheet formed by.

the severance of such cut out therefrom. This punch does not requireadditional operations vor mechanism for complete removal of such cutout.

An important feature of this invention is that the ejecting mechanism isso constructed and arranged thatits action is delayed so that the cutout is ejected from the punch only after the punch.l

has `been completely elevated above the sheet acted upon.

Another important feature is that this delayed I action ejectingmechanism is not only self-contained within 'the punch itself but isself-actuating in that it responds to clean the cut out portion from thepunch after the punch has been lifted a determined spaced distance abovethe sheet of material acted upon by the punch and without theintervention of any additional or auxiliary apparatus actuated bythepress or punch operating machine but automatically when the punchattains a determined height above the sheet of 'materialpunched V 'Afterthe punch has been lifted a determined spaced distance above the sheetof material from which the cut out portion has been severed the punchcleaning -or ejectingmechanism functions to eject the cut out portionfrom'the punch clear of the aperture formed in the sheet of materialpunched. By delaying vthe ejecting action the cut out portion iswithdrawn entirely fromthe sheet of stockI material after the punch isretracted and'following such complete withdrawal is. then ejected fromthe punch. y v

Other objects, advantages, and meritorious features of this inventionwill more fully appear from vthe following description, appendedclaims,v and accompanying drawing, wherein: y Figurel illustrates inside elevation a punch-- embodying this invention,

Fig. 2 illustrates in cross-section a punch embodying'the invention inthe position of severing. t

a portion from a sheet of material,

Fig. 3 4is a plan taken on the line 3-3 of Fig. 1,

Fig. 4 is a View looking up at the bottom of the punch on'the line 4;-4of Fig. 1,

Fig. 5 is a side elevation of a punch embodying the invention and brokenaway showing a slightly modified form of cutting edge,

Fig. 6 is a side elevation partly vbroken away of a punch embodying amodified form of my invention.

The improved punch is illustrated in the olraw-y ing and positioned foroperation. The invention is shown'as 'embodied in a punch or die of circular contour. It is obvious that it might be of any desired shape. Theshape shown is conventional and illustrative only. It is shown is con*nection'with a sheet of fiber board adapted to `be cut thereby. Theextensive use of fiber board in terial with which the punch was capableof functioning.

'I'he punch will be carried by the movable part of a machine which willurge the same with sucient force against the sheet material to be cut bythe punch so as to perform its intended function and such sheet materialwill of course be properly supported. One punch might be used or amultiplicity of punches might be mounted in a form which has movedtoward and away from the sheet material to be cut thereby. Thisassociated apparatus and machine mechanism is conventional constructionand this invention re lates solely to the structure of the'self-contained punch itself and is not concerned with this associatedmechanism.

In the drawing a sheet of material to be cut by the punch is indicatedas I 0. Such material may, as above stated, be composition brousmaterial. `'I'he punch itself embodies a body portion I2 sharpened atone end as at I4 to provide a cutting edge at such end. This body memberis here shown as circular in cross-section and of tubular construction.It is provided with slots IB which are here shown as arranged in twoopposed pairs and extending lengthwise of the body member from that endwhich is opposite the cut end toward the other end but the slotsterminate spaced from such cutting end as shown particularly in Figs. 1,2, 5 and 6.

The cutting end of the punch may be shaped as desired to serve itsintended cutting purpose and depending upon the character of materialand the character of the aperture desired to be' made. In Fig. 5 'aslightly diierent form of cutting edge is illustrated. These featureshave nothing to do with the invention herein claimed and it is obviousthat any type of cutting bevel desired may be given to the cutting edgeof the punch.

In the construction of Fig. 2 the cutting edge is beveled upon theinside as well as upon the outside Ywhile in Fig. 5 the cutting edge isstraight on the inside and the bevel which is a multiple Y one isentirely on the outside surface.

The present invention concerns itself with suchV a punch provided withimproved ejector or knock out mechanism adapted to knock the slug or cutout portion removed from the board by the punch out of the punch in sucha manner that the punch will clear itself at all times during operationso that it may continue to function accurately and efficiently withoutthe necessity of additional operations for its clearance and in such aman- -ner that it will not be left in the sheet of material from whichit was severed.

This ejector mechanism is here shown as formed of a pair of strapelements which extend transversely throughl the body of the punch beingdisposed Within the slots I6. These strap elements cross each otherwithin the body of the punch being disposed at right angles to oneanother and are so bent as to form a knock out y portion 2U within thebody of the punch which is cup shaped so as to receive one end of aspring 22 the opposite end of which spring bears against a springabutment in the form of a plate 24 which plate 24 is removably heldWithin the upper end of the punch by a snap ring 26. The spring tends tourge these ejector straps toward the cutting end of the punch so thatnormally they seat therein as determined by the length of the slots I6.

It will be noted that each strap is so shaped lthat the central knockout area 20 has end extensions which are U-shaped. Each of these U-shaped end extensions has a short leg 28 within the body of the punchand the base of the U or bridge portion 30 rides within the slot I6 andseats in the bottom of the slot under the pressure of the spring 22 asshown in Figs. l, 5 and 6.

Each U-shaped end extension has also a longv outer leg 32 which extendstoward the cutting end of the punch outside of the punch body as shownin Figs. 1, 2, 5 and 6 and is of such a length that when the ejectorstraps or clips are seated in the ends of the grooves as shown in Fig. 1these long leg portions 32 project sup-v,

stantially beyond the cutting end of the punch but the short legs are ofsuch a length that the knock out portions 20 are supported within thebody and do not project beyond the cutting end of the punch. It is dueto this construction that the delayed action of the knock out which isav feature of primary importance is obtained. In

Figs. 1 and 2 these outer legs 32 bear directlyv cut thereby the legs 32or the link 34 first er1-- gages such sheet and the continued dofwnwardmovement of the punch body is against yielding resistance of the spring22 as the knock out or ejector which is made up of the cross straps orclips travels upwardly against the resistance of the spring. When thecutting edge of the punch comes in contact with the board the knock outlportion 2|) of the ejector is elevated substantially above theboard andthis is true when the punch-I is pressed completely through the sheet ofmaterial to be cut as shown in Fig. 2.

In such figure it will be seen that a portion 38 has been severed fromthe board I0 and this portion forms a slug or knock out portion which,v

when the punch is elevated after completing its cutting operation willnormally cling within the cutting end of the punch body and be liftedfromv the sheet of material by the punch. The knock out portion 20 ofthe ejector will not come into play to knock this portion 38 out of thepunch body until the punch body has been lifted a suiiicient distance topermit the knock out portion to move downwardly as the spring expands.It

will therefore be seen that the punch body willk have completely clearedthe board or sheet mate rial from which the cut out part was severedbefore the ejector functions to knock the slug i from the punch body. Itis this delayed action of the punch which clears the cut out portionv insuch a manner that it does not fall back within the' sheet of materialfrom which it was cut and clears it entirely by the action of the punchmechanism itself as it moves away from the sheet operated upon. tirelyautomatic in its functioning. It is selfcontained within the punch. Itis simple and inexpensive in construction. If the spring 22 is brokenthe plate 24 may be removed and another spring inserted in place. Repairis easily accomplished.

What we claim is:

1. A punch comprising a tubular body having a cutting edge at one endand having slots ex- 'ce The ejector mechanism is enbody and providedwith supports extending through said slots and slidable lengthwisethereof pairs o i opposite vslots extendingirom lsaid oppositeendlengthwise of the body andterminattending lengthwise of the body.vterminating spaced from said cutting end, ejector mechanism havingaknock out portion disposed within the and adapted to support said knockout portion within thebody when the supports are seated withinv the endsof the slots adjacent to the cutting end vof the body,rspring means'acting upon said ejector mechanism to yieldingly urge'said knock outsupports to seat within said slots, Asaid knock out supports having legsdisposed exteriorly of the body and of a length to extend beyond thecutting 'end of thebodywhen the knock out supports are seated withinsaid slots.

2. A punch comprising a tubular body having acutting edge at one end anda spring' abutment at the opposite end and having opposed slotsextending lengthwise of the bodyand terminating spaced from said cuttingend, ejectormechanism having a knock' out portion disposed within saidbody and provided with `opposed supporting 'portions vextending throughsaid slots and vslidable lengthwise thereof and adapted to seat withinlthe ends of the slots adjacent to the cutting endv of the body and whenso seated adapted to sup- *i port said knock out portion within thebody, said supports provided with legs outside of the body extendinglengthwise thereof and of a length to terminate spaced outwardlybeyondthe cutting endof the body when the knock out supports are seatedwithin said slots, and a spring seated at one end against said springabutment adapted to yieldingly urge said knock out toward the `cuttingend of the body.

3; A punch comprising a tubular body having a cutting edge at one endand a spring abutment at the opposite end and having opposed slots eX-tending-lengthwiseof the body and terminating spaced from said cuttingend, ejector mechanism mounted within said slots for slidablemovementlengthwise therethrough and including a knock out portiondisposed within said body and U-shaped leg portions extending throughsaid slots with the b-ase of each U-shaped leg portion slidably disposedwithin its slot and adapted to seat in the end thereof adjacent tothecutting end of the body, each U-shaped leg portion having a short legwithin the body and a long leg outside of the kbody whereby the knockout portion is supported within the body when the U- shaped legs are.seated within said slots and the outer long legs extend beyond thecutting end of vthe body, and a spring bearing at one end against saidspring abutment and at'the opposite end against said knock out portionto yieldingly-urge said ejector toward the cutting end ofthe body. i

4. A punch comprising a tubular' body having a cutting edge at one endand a spring abutment at the opposite end and having opposed slotsextending lengthwise of thebody and terminating spaced from said cuttingend, ejector mecha-- nism comprising a strap` having a central knock outportion disposed within the body and having U-shaped end portionsextending through said slots and adapted to seat within ends of theslots adjacent to the cutting end of the body, each U`- shaped endportion having a short leg within' the body anda long leg outside of thebody, such short leg being of such a length that the central knock outportion of the strap is supported. within the body when each U-shapedleg portion is seated within its slot and said long legs ybeing of sucha length that the ends thereof project betransversely through the yondthe cutting end of `the body when the U- shaped end portion is so seatedwithin its slot.

5. A punch comprising a tubular body having a'cuttingedge at one endanda removable spring abutment at the opposite end and having two ingspaced from said cutting end, a snap ring holding said abutmentreleasab-ly in position, ejector mechanism comprising a strap for eachpair of slots extending transversely through the body and through saidslots, each strap having a central portion disposed within the body andadapted to serve as an ejector knock out, such straps crossing eachother within the body, each strap having U-shaped end portions disposedwithin the slots for slidable movement length- Awise therethrough. keachLl-shaped end portion having a long leg outside of the body of a lengthto extend beyond the cutting end oi the body when the U-shaped endportion is seated within and having a short iovernent of the ejectortoward the cutting end of the body, said ejector having a knock outportion .disposed within said body andhaving supporting legs disposedoutside ci the body and eX- tending beyond its cutting end when theejector reaches its limit of movement toward said cutting end.

7. A punch comprising a hollow body having a cutting edge at one end, anejector extending transversely through the body and slidable lengthwisethereof, means yieldingly urging said ejector toward the cutting end ofthe body,' means limiting the movement of. the ejector toward saidcutting end of the body, said ejector having a knock out portiondisposed within said body and a supporting portion disposed outside ofthe body and extending toward the cutting end of the body substantiallybeyond the knock out portion of the ejector.

8. A punch for cutting a part from a sheet of material including amember within the punch yieldingly` urged rtoward the cutting edgethereof and adapted to engage the cut out part and eject `the same fromthe punch, said membery having a part directly connected and adapted toengage the sheet of material duringthe .cutting operation and hold themember back` in its movement toward the cutting edge of the punch so.that it does not engage the cut out part untily after the punch has beenretracted a spaced distance from the sheet of material.

9. Punch mechanism comprising a hollow punch body having a cutting end,directly connected ejector and stock. stripper means having its ejectorportion disposed within the punch body and having its stock stripperportion disposed externally of the punch body, and mechanisrn actingupon said ejector and stock stripper means jointly and as a unit to urgethe same toward the cutting end of the punch body. f 10. Punch mechanismcomprising a hollow punch body having a cutting end ejector and stockstripper means having its ejector portion disposed within the punch bodyand having its stock stripper portion disposed externally thereof, saidejector portion and stock stripper portion being directly connected by aU-shaped portion bridging a part of the punch body Wall for movement asa unit toward and away from the cutting end of the punch, said stockstripper portion being in advance of the ejector portion, and meansengaging said ejector and stock stripper means to urge the same as a.unit toward the cutting end of the punch.

11. Punch mechanism comprising, in combination, a hollow punch bodyhaving a cutting edge, an ejector supported within the punch body formovement toward and away from the cutting edge and a stock stripperdisposed outside the punch body and carried by the ejector for movementtherewith, said stock stripper being disposed in advance of the ejectortoward the cutting edge of the punch, and spring means yieldinglyengaging the ejector to urge the ejector and stock stripper as a unittoward the cutting edge of-the punch.

12. Punch mechanism comprising, in combination, a hollow punch bodyhaving a cutting edge, an ejector supported within the punch body, astock stripper disposed outside of the punch body,

' a bridging portionconnecting said ejectorv and 13. Punch mechanismcomprising, incombina-- l tion, a hollow punch body having a cuttingedge,

an ejector supported within Ythe punch body, a

stock stripper disposed `outside ofthe punch body,

a bridging portion connecting said'ejector and stock stripper formovement as `a unit toward and ,l

away fromthe cutting edge of the punch, and,

springmeans disposed'within the punch body and acting upon said ejectoroperable to urge saidv v ejector and stock stripper as a unit towardsaid cutting edge. l

' l DAVIDE. STROMBERG.n

. JOSEPH E. CARLSON.

